One of the current major problems for aircraft, commercial as well as military, is that of providing maximum operational capability under adverse weather conditions. For both commercial and military aircraft, two of the primary limitations are the ability to navigate, and the ability to see a target within a scene. The target may, for example, be the end of the runway during landing, or a military target under attack and/or observation.
Several methodologies have been and/or presently are used or are under consideration for improving the ability of airborne aircraft systems to operate under adverse weather conditions. One such methodology is to navigate and, in the case of military aircraft, deliver weapons using radar. This methodology has at least two significant disadvantages. First, it is dependent upon active sensors which, in the case of military aircraft, increase the vulnerability of the sensor-containing airborne system to adverse detection systems. Second, radar systems generally have relatively poor resolution, especially those that operate in real time.
Another methodology is the use of optical sensors, such as infrared (IR) sensors, under the assumption that the airborne system can operate below the significant adverse weather conditions for the final approach to the runway or target. However, such systems cannot operate properly when the conditions are too adverse for optical (e.g. infrared) use.
Attempts have been made and are ongoing to combine radar and infrared imagery for use by the operator of an airborne system. One such alternative is to obtain a snapshot synthetic aperture radar (SAR) map far out from the target, and then use the IR imagery to enhance the SAR map. A further such proposal has been to transform the SAR map and to combine it with the real-time IR imagery in order to enhance the ability of the operator to discriminate targets from clutter. These attempts may provide better information than the above-described systems which use radar alone or infrared sensors alone. However, adverse weather can still negate or substantially diminish the ability to obtain useful information from IR sensors or from other types of sensors, including radar. A different methodology from those practiced and/or presently contemplated by the prior art is required for the next generation of target-viewing airborne systems, whether the target is an airport runway or military objective.